Rotary pump



July 8,1947`. w. czARNEcKl ROTARY PUMP vFiled March 15, 1945' 2Sheets-Sheet 2 Patented July 8, 1 947 ROTARY PUMP .Walter Czarnecki,Eddington, Pa., assignor'to Eddington Metal Specialty Company,Eddlngton, Pa.,.a partnership Application 'March 15, 1945,V Serial No.582,837

This invention relates to rotary pumps and is concemed primarily with arotary pump including movablev vanes as the elements which build uppressure on the fluid; u

The rotarytpump of the typewith `which this invention is concerned and'which' is now meeting with widspread use,'comprises` essentially acasing `orrhousing which provides a substantially cylindrical chamberwith which communicates the lnlet and the Outlet. Rotatably mounted inthis casing is a rotor which is also substantially cylindricalv inshape. The axis of the rotor is disposed 'eccentrically with respect to.the axis of the Vchamber to establish a crescent shape space betweenthe rotor and the housing, and which i space extends from the inlet tothe outlet.

In a more developed pump of this type, springs have-also been employedas means for actuating the vanesr However, any mechanism of this typeincluding springs is rendered highly complex be-l cause of the ve'rypresence of. the springs and ;considerabledifficulty has beenlexperienced not only in Originally assembling the pumps but also inservicing them,

- A 'still more refined development embodied in the known art, is theuse of end rings which cooperate with the vanes to maintain the outeredges thereof in 'engagement with the wall of the boardedefining thechamber. The use of such end. rings is, doubtlessly, an improvement overearlierpumps of this type, but the presence of the end rings increasesthe size of the assembly for any given size rotor, and, in addition,considerable difliculty and-inconvenience is experienced inproperlyassembling the vanes with respect to the rings in the originalproduction and also in any later service Operations which might benecessary.

-In view of the condition of the art of rotary pumps as above outlined,and' particularly because of the complex nature ofV the efiicient pumpsnow available, this invention has, as its foremost objective, theprovision of a rotary pump of'the -type above set forth, in which theOperating mechanism is highly simplifled, the number of 55 2 Claims.(Cl. 103-135) moving parts maintained 'at' an absolute minimum, and theefiiciency of operation 'kept at a maximum. In attaining this end, theinvention achieves the lcomplete elimination of-springs, end rings orother moving parts employed for' actuating thel vanes, which heretoforehave been deemed necessary to efllcient operation.

`A further object of the invention is the provision of a rotary pump ofthe cl' aracter aforesaid in which the rotor and vanes areconstructed'so as to supplement the centrifugal force developed byrotation of the rotor, by pressure fluid to' move the vanes outwardly.In order for a pump'of this type to operate with required efliciency, itis necessary that the vanes fit into the rotor slots with a fairly snugfit. When the meeting parts are machined into a smooth condition, a'sealis'efiected which, not only tends to bind the engaging surfaces, butwhich'also creates a partial vacuum beneath the vanes when the lattertend to move outwardly, and this sealing effect is greatlyincreased'when the pump is employed ona hydraullc'medium, vsuch as oil,which forms a sealing film betweenv the'surfaces. With this particularcondition in mind, the invention has in view, as a further object, theprovision of a rotary pump of-the type :above described, which includesmeans forbreaking the seal between the vanes and the walls of the slotwhich receive them.

Both the objects of breaking fthis seal,=which impairs the slidingaction of the vanes, and that of utilizing fluld pressure, asasupplemental actuating force for moving the vanes outwardly,-areaccomplished by'the particular construction of the rotor and vanes whichis obtained 'byv'thls invention. f

More in detail, the invention has as its object the provision of arotary pump of therchar'acter aforesaid, which includes a sliding vane,the forward face of which is'formed with a'slot communicating betweenthe upperand lower edges of the vane. In a preferred embodiment of theinvention, two or more of theseslots maybeemploy e;d A and they serve'tobreak the seal between the faces of the rotor slot'and vane, and' alsoto bring the fluid under pressure down beneath the inner' edge ofthervane, to move it outwardly.

Yet another object of thefinventiomis the provision in a rotary pump ofthe character aforesaid of a vane having its forward face slottedtogether with a channel on the inner edge of the vane which establishes'communication between' the u slots.

To the end of rendering the slotsfmore effeci 3 tive, the invention hasas 'a further object, the provision of a rotary pump of the typeindicated, which includes a rotor formed with slots receiving vanes,with the cylindrical face of the rotor cut away immediately in front ofthe forward faces of the vanes. Thus, as the rotor is turned, the fluidunder pressure is readily admitted to the slots.

Another object of the invention is the provision in a rotary pump of thecharacter aforesaid, of a vane which includes a closed channelextendingupwardly from edge thereof and which communicates with anaperture that opens on to the front face of the vane at, -or immediatelyadiacent to,` the upper or outer edge thereof. In this form of theinvention two or more of lthese closed channels may also be employed andthey bottom or inner edge become apparent, and in part be hereinafter`stated as the description of the invention proceeds.

The invention, therefore, comprises a rotary pump including a slottedrotor, together with vanes slidably assembled in the slots. The rotor isdesigned for rotation in one direction, and the forward face of eachvane is formed with a plurality of slots extending from the outer edgeof each vane to the inner or bottom edge, and this inner or bottom edgeis formed with a channel establishing communication between the severalslots.

For-a full and more complete understanding of the invention, referencemay be had to the following description and accompanying drawings,

whei'ein:

Flgure l is a section through those parts of a rotary` pump with whichthis invention is immediately concerned: i

Flgure 2 is another sectional view taken at right angles to the showingof Figure 1; i

Figura 3 is an enlarged detailedperspective of the rotor per se;

Flgure 4 is a detailed cross section through one of the vanes;

Figura 5 is a. detailed perspective of one of the vanes;

Figure 6 is a detailed cross sectional view similar to Flgure 4, of onemodification;

Figure 'I is a detailed perspective of the vane, the cross section ofwhich is shown in Figure 6;

Flgure 8 is a cross section through yet another form of vane; and

Flgure 9 is a detailed perspective of the form shown in r'igure 8.

Beferring now to the drawings wherein like reference characters denotecorresponding` parts, and first more particularly to Figures 1 and 2, arotary pump embodying the improvements of this invention is shown ascomprising a housing or casing I0, which is formed with a cylindricalbore and a second cylindrical bore |2 that communicates with the boreII. It is important to note that the axes of the bores and |2 do notalign, but rather are eccentrie or offset with respect to each other.The end of the bore 2 is closed by a cover".plate |3 which may besecured to the housing in'any preferred manner, such as by screwfastening elements of the type indicated at Il. The cover plate I3 isformed with a cirthe inner or bottom may be connected at'the by a cross'channel formed i on the inner edge of the vane.

Viso

outer end of the shaft 20 is deformed out of a true circle to providefor engagement, by suitable source of power, for rotating the shaft.Such deformation may take the form of the flat indicated at 2 I.

The large ring 22 is tightly fitted in the bore |2 and abuts theshoulder 23 which divides the bores I I and |2. This ring 22 is providedwith an opening through which the shaft 20 extends. That portion of thebore |2 between the cover plate |3 and the ring 22, together with theseelements. deflne the pressure chamber of the pump which is designated24. It is notable that the shaft 20 carries a bearing 25 adjacent to theouter end of the bore |I.`

Interposed between the ring 22 and the bearing 25 is a sealing assemblywhich is no particular part of the invention.` It merely serves toprevent leakage of the hydraulic fluid along the shaft 20. As is clearlyshown in Figure 2, the casing |0 is formedtwith a fluid outlet 20 whichcommunicates with the pressure Vchamber 24, and the fiuid inletindicated at 21 also communicates with the pressure chamber 24, and alsowith a by-pass channel shown at 123. This `by-pass channel is also notparticularly pertinent to the present invention, and is merelyillustrated because it is employed in one practical adaptation whichbypasses fluid. The present invention is concerned prmarily with whattakes place in the action on the fluid between the inlet 21 and outlet26, within the chamber 24.

Referrlng now more particularly to Figures 2 and 3, `a rotor 29 is shownas being keyedito the shaft 20, as indicated at 30. The rotor 20 is thusdrivably mounted on the shaft 20 for rotation onan axis eccentric to theaxis of the bore |2. The rotor 29 is provided with a plurality of slots3| which, it will be noted, are disposed at an angle to any radius ofthe rotor. This angular disposition of the slots 3| is a feature ofparticular importance as will be later pointed-out.

At this point it is well to note that a rotary pump of this type willordinarily be designed for rotation in one direction. This direction maybe either clockwise or counterclockwise,` but unless the direction ofrotation is determined, the pump is not susceptible of operation in areverse direction to build up pressure of fluid. In the embodiment ofthe invention shown in Figures' 2 and 3, the rotor is designed forrotation in a clockwise direction.

Speaking with reference to this direction of rotation, the forward edgesof each of the slots 3| are cut away as indicated at-32. This cut awayor flat is of great importance, as will later become apparent. I

The number of slots 3| may, of course, vary in accordance with theengineering requirements of any particular installation. The numbershown in the drawing is taken purely for' illustrative purposes.

of vane which is provided in accordance with the the vane which isreferred to in its entirety by the reference character V comprises asubstantally solid block, preferably of metal, having a front face 33and a rear face 34, a top or outer edge 35, a bottom or inner edge 38and end walls 31. It will be noted that the top or outer edge 35 iscurved to conform to the curvature of 'the bore |2, as the edges 35 ofall the vanes V are intended to slidably engage the wall of bore |2.

Extending from the top edge 35 to .the bottom edge 36, and formed in thefront face 33 of the vane V, are a pair of channels 36, and it isparticularly important to note that the channels 38 are most shallow atthe outer edge and deepest at the inner edge, providing in effecttapered or the bore |2 to provide for maximum efllciency in theoperation of the pump.

, The angular disposition of the vanes is of particular importance. Inmany instances it is desirable to employ a rotor of small radius and yethave a comparatively large degree of eccentricity between the rotor andthe pressure chamber. This means there is a large space to be spanned bythe vane. Not only must the vanes extend completely across the space ofeccentricity, but there must be enough of the vanes left in 'the' slotsto adequately support them. This fiared channels that enlarge in crosssection from the outer edge to the inner edge.

Formed on the bottom or inner edge 36, and extending between the endwalls 31, is communicating channel 39 which provides a space forpressure fluid beneath the entire length of the vane V.

Figures 6 and '7 show one modiflcation in the construction of the vanes.In this fon'n the vane is identified by the reference Character V1. Thisvane V1 includes the same front and rear faces, top and bottom edges andend walls described above in connection with the vane V. However,

three of the channels 38 are illustrated rather than only two. The pointof distinction between the forms of invention shown in Figures 4 and 5on one hand and Figures 6 and 7 on the other is that in Figures 6 and 7the communicating channel 39 is eliminated and the lower ends of thechannels 38 terminate in enlarged recesses 40 which, as is clearly shownin Figure 6, extend be- 'tween the front and rear faces 33 and 34.

The operation of the pump will be` the same re- I gardless of which ofthe vanes V, V1 or Vz are employed. The shaft 20 will be driven from asuitable source of power and rotates the rotor 29 in a clockwisedirection (speaking with reference to showings of the drawings), in thatportion of the bore |2 opposite the pressure chamber 24. `VThe outeredges 35.0f the vanes due to their engagement 'with the wall of' bore |2are forced substantially completely within the slots 3|.

-As these vanes pass the inlet 21 they tend to move outwardly due to thecentrifugal force. This tendency is supplemented by the fact that thefiuid under pressure is admitted to the upper extremities of thechannels 38 and passes downwardly through these channels beneath thebottom edge 36 and, thus, moves the vanes out to their slots. Thetendency of the snug intertting Walls of the vanes and slots to createa`seal or partial vacuum beneath the vanes is destroyed by the presenceof these channels 38. Thus, it will be seen that the vanes V at alltimes completely bridge the space between the rotor and means that theremust be a sufiicient distance between the outer and inner edges 'of thevanes to accomplish this end. If the slots were true radial slots, inmany instances there would not be suflicient depth in the slots toachieve this end. The angular disposition of the slots provides foradequate extent of the vanes.

While preferred specific embodiments of the invention are hereinbeforeset forth, it is to be clearly understood that the invention is not tobe limited to the exact constructions illustrated and described becausevarious modifications of the details may be provided in putting theinvention into practice within the purview of the appended claims.

What is claimed is:

1. In a rotary pump having a rotor and a casing in which the casing isprovided with a substantially enclosed cylindrical chamber with inletand Outlet connections, means eccentrically mounting the rotor in thecylindrical chamber of the casing, said rotor having a plurality ofslots rectangularshape in cross section extending inward from theperiphery thereof, said 'slots having parallel sides and said'sidespositioned at acute angles to radially extending planes from the centerof the rotor with the slots sloping backward from the direction ofrotation of the rotor, the peripheral surface of the rotor provided withbeveled surfaces adjacent the leading edges of the slots, and aplurality of vanes slidably mounted in said slots, said vanes havingarcuate outer ends, longitudinally extending recesses in the inner edgesand passages across the leading faces thereof providing continuouscommunicating means between the periphery of the rotor through thesp'aces provided by the said beveled surfaces and the recesses in theinner edges of the vanes, whereby fluid under pressure in front of thevanes passes inward through the said passages in the vanes building uppressure behind the vanes for forcing the vanes outward accentuating thecentrifugal force in the rotor.

2. In a rotary pump having a rotor and a casing in which the casing isprovided with a substantially enclosed cylindrical chamber with inletan'd Outlet connections, means eccentrically mounting the rotor in thecylindrical chamber of the casing, said rotor having a plurality ofslots rectangular-shape in cross section .extending in- Ward from theperiphery thereof, said slots having parallel sides and said sidespositioned at acute angles to radially extending planes from the centerof the rotor, with the 'slots sloping backward from the direction ofrotation of the rotor, the peripheral surface of the rotor provided withbeveled surfaces adjacent the leading edges of the slots, and apluralit-y of vanes slidably mounted in said slots, said vanes havingarcuate outer ends, longitudinally extending recesses in the inner edgesand passages across the leading faces thereof providing continuous com-

